I am creating a carousel slider of images. In there some images/icons are smaller than others. And I want to align all the images/icons in the center without any extra classes for those small images. I was trying vertical-align: middle; or display: inline-block; and so on. 
Screenshot_1.png is the example slider and Screenshot_2.png is the slider that I am looking for.
 

<div id="owl-demo" class="custom-carousel">
  <div class="item"><img src="img.png" alt="img"></div>
  <div class="item"><img src="img.png" alt="img"></div>
  <div class="item"><img src="img.png" alt="img"></div>
  <div class="item"><img src="img.png" alt="img"></div>
  <div class="item"><img src="img.png" alt="img"></div>
  <div class="item"><img src="img.png" alt="img"></div>
</div>
 
     
     
    